Everything MCAT 2015

Question 1

The frontal lobe involves working memory, task switching, and dynamic filtering. It does not involve perseveration. What is perseveration ?

Answer 1

Perseveration is when the subject applies the same rule again and again to a task, even when the experimenter has indicated otherwise.

Question 2

When does experimenter bias occur?

Answer 2

It occurs when the experimenter either consiously or subconsciously alters the results to meet their expectations

Question 3

A 1000kg rocket ship, traveling at 100 m/s is acted upon by an average force of 20kN applied in the direction of its motion for 8 seconds. What is the change in velocity of the rocket?

Answer 3

F= ma. Since the force is acting in the same direction, find the acceleration so we can find new velocity. a=F/m. Then, recall average acceleration is a=change in v/ change in t. New velocity would be change in velocity= acceleration(delta t). Pluggin in from the first formula you get velocity change= F(delta t)/ m.

20,000N(8)/ 1000 kg= 160 m/s

Question 4

An elevator is designed to carry a max weight of 9800 N (including its own weight ) and to move upward at a speed of 5 m/s after an initial period of acceleration. What is the relationship between the max tension in the elevator cable and the max weight of the elevator while the elevator is accelerating upward?

Answer 4

The forces on the elevator are the tension upward and the weight downward, so the net force on the elevator is the difference between the two. for an elevator to accelerate upwards the tension in the cable will have to be greater than the max weight so that there is a net force directed upwards.

Question 5

A 20 kg wagon is released from rest from the toop of a 15m long lane, which is angled at 30 degrees with the horizontal. Assuming that there is friction between the ramp and the wagon, how is this frictional force affected if the angle of the incline is increased?

Answer 5

The frictional force decreased because..

F= uk(Normal force)
F=uk (mgcostheta). As cos theta increases, the value decreases, meaning that if the slant was made more steep, there would be less frictional force.

Question 6

Is distance a vector or a scalar

Answer 6

It is a scalar

Question 7

Centrifugal force always acts ______ to the centripetal force vector

Answer 7

antiparallel

Question 8

The area of the brain through which conscious and unconscious signals travel is known as the

Answer 8

Diencephalon

Question 9

Which of the following is the correct sequence of the development of a mature sperm cell?

Answer 9

Spermatogonium → 1° spermatocyte → 2° spermatocyte → spermatid → spermatozoan

Diploid cells called spermatogonia differentiate into primary spermatocytes, which undergo the first meiotic division to yield two haploid secondary spermatocytes. These undergo a second meiotic division to become immature spermatids. The spermatids then undergo a series of changes leading to the production of mature sperm, or spermatozoa.

Question 10

Which of the following correctly pairs the stage of development of an egg cell with the relevant point in a woman’s life cycle?

Answer 10

At ovulation—metaphase II
From the time of birth until shortly before ovulation, all egg cells are arrested at the prophase stage of meiosis I. These cells are referred to as primary oocytes. At ovulation, the egg cell has completed meiosis I and is now arrested in metaphase II as a haploid cell called a secondary oocyte. When a sperm penetrates the outer layers of the secondary oocyte, it completes meiosis II to become a mature ovum.

Question 11

A researcher wishes to incorporate a radiolabeled deoxyadenine into the genome of one of the two daughter cells that would arise as a result of mitosis. What is the latest stage of cellular development during which the radiolabeled deoxyadenine could be added to achieve this result?

Answer 11

To ensure that the labeled deoxyadenine will be incorporated into the DNA of one of the daughter cells, we have to insert the nucleotide before DNA replication has been completed. Because replication occurs during S stage, we could introduce the deoxyadenine during G1 or S stage. Because G1 precedes S, the latest point the deoxyadenine could be added is the S stage.

Question 12

Upon ovulation, the oocyte is released into the:

Answer 12

This subtle point about ovulation eludes most students and remains hard to believe until the organs are examined in anatomy class in medical school. The ruptured ovarian follicle releases an oocyte into the abdominal cavity, close to the entrance of the fallopian tube. With the aid of beating cilia, the oocyte is drawn into the fallopian tube, through which it travels until it reaches the uterus. If it is fertilized in the fallopian tube, it will implant in the uterine wall. If fertilization does not occur, it will be expelled along with the uterine lining during menstruation.

Question 13

Which of the following statements correctly identifies a key difference between mitosis and meiosis?

Answer 13

The key differences between mitosis and meiosis primarily appear during meiosis I. Of note, synapsis and crossing over occurs during prophase I, and homologous chromosomes are separated during meiosis I (rather than sister chromatids, as in mitosis). While the location of the centromeres relative to the equatorial plate may seem a trivial point, it is representative of the fact that homologous chromosomes line up on opposite sides of the equatorial plate in meiosis, in contrast to the alignment of each chromosome directly upon the metaphase plate in mitosis.

Question 14

Which of the following correctly describes a difference between nerves and tracts?

Answer 14

Nerves are collections of neurons in the peripheral nervous system and may contain multiple types of information (sensory or motor); they contain cell bodies in ganglia. Tracts are collections of neurons in the central nervous system and contain only one type of information; they contain cell bodies in nuclei.

Question 15

When the potential across the axon membrane is more negative than the normal resting potential, the neuron is said to be in a state of:

Answer 15

When the potential across the axon membrane is more negative than the normal resting potential, the neuron is referred to as hyperpolarized. Hyperpolarization occurs right after an action potential and is caused by excess potassium exiting the neuron.

Question 16

Each of the following is considered a part of a person’s self-concept EXCEPT:

Answer 16

Self-concept is defined as the sum of all of the ways in which we see ourselves, including who we are, as in choice (D), who we were in the past, choice (A), and who we may become in the future, choice (C). The ought self, while closely related to self-esteem, is our appraisal of how others see us, and is not a part of our self-concept.

Question 17

A person keeps his desk extremely tidy and becomes very nervous whenever things are disorganized or out of place. In which of the following stages would a psychodynamic therapist say the man had become fixated?

Answer 17

Both excessive organization and excessive sloppiness are indicative of fixation in the anal stage of psychosexual development—what is commonly referred to as anal-retentiveness.

Question 18

Matt and Cati discuss the reasons why they avoid driving above the speed limit. Matt says that he wants to avoid a traffic fine, while Cati says that speeding is dangerous and, if everyone did it, there would be more accidents and people would get hurt. According to Kohlberg, which of the following describes the phases of moral reasoning demonstrated by Matt and Cati, respectively?

Answer 18

Matt’s reasoning reflects a desire to avoid punishment, which reflects stage one in Kohlberg’s preconventional phase (obedience). Cati’s reasoning takes into account social order, reflecting stage four in the conventional phase (law and order).

Question 19

A child finds that she cannot make an origami swan by herself, but is able to do so when observing and being assisted by an adult. This scenario is described in the ideas of which of the following theorists?

Answer 19

This situation is best described by Lev Vygotsky’s zone of proximal development theory, which holds that children are often unable to perform tasks by themselves, but can complete the task with the help of a more knowledgeable other.

Question 20

A man feels extremely guilty after having an extra-marital affair. According to the psychodynamic perspective, which of the following is responsible for this anxiety?

Answer 20

The superego is responsible for moral guilt when we do not live up to our ideals. While the id and the libido, choices (A) and (D), may be responsible for the urge to have an affair, the superego is responsible for the anxiety one feels afterwards.

Question 21

Researchers discover that polymorphisms in the DRD2 gene can be associated with thrill-seeking behavior, and that individuals with certain forms of the gene are more likely to become extreme athletes and have more dangerous hobbies. Which of the following theories is supported by this discovery?

Answer 21

This research supports a link between genetic expression and behavior, which is a central tenet of the biological perspective. The social cognitive perspective also holds that people’s behaviors and traits shape their environments, which in turn have an effect on their identity, so the discovery also supports this perspective. Behaviorism is not supported, as the discovery is not related to rewards and punishments.

Question 22

An EMT sees himself as a bit of a rebel, but is highly sociable and is able to keep calm in an emergency. This person would likely score in the lower range of which of the following traits?

Answer 22

As a rebel and a sociable person, this individual would score highly on both psychoticism and extraversion, respectively. Neuroticism is associated with high emotional arousal in stressful situations, so being able to keep calm in an emergency is a sign of low neuroticism.

Question 23

Stockholm Syndrome is a phenomenon in which a victim of a kidnapping or hostage situation may begin to identify with or even feel affection for his or her captors. A psychoanalyst might explain Stockholm Syndrome by citing which of the following defense mechanisms?

Answer 23

Reaction formation is a defense mechanism that converts unwanted feelings into their exact opposite. A psychodynamic theorist would say that the terror and hatred one feels toward his or her captor might be unconsciously turned into affection in an effort to reduce the stress of the situation.